/*
 * Copyright (c) 2012 swing-on-fire Team
 * 
 * This file is part of Swing-On-Fire (http://code.google.com/p/swing-on-fire), licensed under the terms of the MIT
 * License (MIT).
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated
 * documentation files (the "Software"), to deal in the Software without restriction, including without limitation the
 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included in all copies or substantial portions of the
 * Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
 * WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
 * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */
package com.google.code.swingonfire.utility.interpolation;

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

public class SequentialInterpolation implements Interpolation
{

    private static class Entry implements Comparable<Entry>
    {
        private final double startFraction;
        private final Interpolation interpolation;

        public Entry(double startFraction, Interpolation interpolation)
        {
            super();

            this.startFraction = startFraction;
            this.interpolation = interpolation;
        }

        public Interpolation getInterpolation()
        {
            return interpolation;
        }

        @Override
        public int compareTo(Entry o)
        {
            if (startFraction < o.startFraction)
            {
                return -1;
            }

            if (startFraction > o.startFraction)
            {
                return 1;
            }

            return 0;
        }
    }

    private final List<Entry> entries = new ArrayList<Entry>();

    private double minimum;
    private double maximum;

    public SequentialInterpolation()
    {
        super();
    }

    public SequentialInterpolation add(Interpolation interpolation)
    {
        return add(0, interpolation);
    }

    public SequentialInterpolation add(double startFraction, Interpolation interpolation)
    {
        entries.add(new Entry(startFraction, interpolation));

        Collections.sort(entries);

        minimum = Double.MAX_VALUE;
        maximum = Double.MIN_VALUE;

        for (Entry entry : entries)
        {
            if (entry.getInterpolation().getMinimum() < minimum)
            {
                minimum = entry.getInterpolation().getMinimum();
            }

            if (entry.getInterpolation().getMaximum() > maximum)
            {
                maximum = entry.getInterpolation().getMaximum();
            }
        }

        return this;
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public double getMinimum()
    {
        return minimum;
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public double getMaximum()
    {
        return maximum;
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public double calculate(double value)
    {
        value = Interpolations.trimInterpolationValue(value);

        for (int i = 0; i < (entries.size() - 1); i += 1)
        {
            if ((value >= entries.get(i).startFraction) && (value < entries.get(i + 1).startFraction))
            {
                value =
                    (value - entries.get(i).startFraction)
                        / (entries.get(i + 1).startFraction - entries.get(i).startFraction);

                return entries.get(i).interpolation.calculate(value);
            }
        }

        value =
            (value - entries.get(entries.size() - 1).startFraction)
                / (1 - entries.get(entries.size() - 1).startFraction);

        return entries.get(entries.size() - 1).interpolation.calculate(value);
    }

}
